Extra Check Valve
We had the same problem on our 2006 45 CC. The problem with the existing shower sump system, is that the small "flapper" type of check valve that is built into the shower sump just will not keep the water that is left in the discharge line, from draining back into the sump. When this happens, and you leave the switch in the "on" position, the sump refills, the pump goes on, the water drains back, and it just keeps on going. We added a second in-line check valve in the discharge hose just a few inches outside the sump box. While it helps, it does not fully correct the problem. If you notice the pump that is supplied with the shower sump(I believe it is an Attwood) is wired for a second (momentary type) switch that if wired correctly, when turned on, will run the pump weather or not the float switch is activated. By installing this you can run the pump, and actually pump it dry, so it will not cycle on and off. By the way we only turn on the switch that runs the float when we are on the boat, and turn it off when we leave. I hope this helps.
Best Regards,
Jeff
